A cylinder head of an Internal Combustion (IC) engine includes a coolant jacket to circulate coolant, containing water, through the cylinder head to facilitate transfer of excess heat away from the cylinder head. Coolant from the cylinder head is generally discharged towards a crankcase through an outlet hole provided in a flange of the cylinder head. The outlet hole is susceptible to failures caused by mechanical fatigue due to a combination of mean and alternating stresses applied to the cylinder head by a crab during initial bolt-up and combustion events, respectively. Once the crack in the outlet hole begins to propagate, coolant can leak out of the cylinder head and cause engine failure due to loss of coolant pressure.
U.S. Pat. No. 5,195,468 describes an outlet end cooling system for a cylinder head of a locomotive engine that includes a modified water pathway in the cylinder head, an outlet therefrom exiting from an upwardly directed surface of the cylinder head, and further including a modified rocker arm support having a planar bottom support surface and having an inlet port therein which is engageable with an outlet port in the cylinder head. The support has a water pathway therein which terminates in a nipple, the nipple extending past the cylinder head and downwardly along a side wall of the cylinder head into engagement with a remaining portion of the waterway. The improved outlet end allows for equal thickness of the side wall around the entire extent thereof, and eliminates a temperature gradient in an area of the cylinder head underlying a crab plate engaged thereover, virtually eliminating cracking and extending the useful life of the cylinder head.